It depends entirely on the desert, of course, but my deserts are done in light tans and yellow colors, with brown textures for contrast. In TRS04 I use the lighter colors from the USA and Australia textures and sweep on medium size swaths of the detail colors I'm using and then fill the baseboard with a USA dry grass texture.
Favorite colors from Australia include Brown Grass, Rocky Dirt and Grass & Dirt, with a hint of Scrub washed on lightly in the low places where water collects
USA colors are Grain and Sandstone, with Yellow Grass or Kahki Grass for the fill. Australian Sandstone is my favorite for rocky outcroppings and cuts, mixing two or more textures for variety.
I also go to the Britain textures for a Dry Long Grass in most of the low spots, that being as green as it usually gets.
Good luck with your deserts.